Not for nothing are the leaves described as "sword-like" - they are capable of inflicting a deep cut in hands not protected by gloves! Winter protection is essential. Either bring the plants inside or provide them with a deep mulch. ...
Shoot senescence in herbaceous perennials of the temperate zone: identifying drivers of senescence pace and shapesenescence shapesenescence pacespecific leaf arealeaf dry matter contenthabitat productivityshoot lifespansenescence upscalingPerennial herbaceous species form their above‐ground parts every year anew...